Create a YANG-based data model for PED files

[mpeuster]

Use a YANG model to have a clear schema for the PED files. This can also serve as input to IETF work.

Developments: https://github.com/mpeuster/tng-sdk-benchmark/blob/feature-73/models/

YANG background

• Wikipedia (lots of useful pointers to RFCs etc.)
• RFC7950 YANG Data Modeling Language
• https://blogs.cisco.com/getyourbuildon/yang-opensource-tools-for-data-modeling-driven-management
• https://wiki.onosproject.org/display/ONOS/YANG+Tools
• https://whatis.techtarget.com/definition/YANG-data-modeling-language
• YANG for Dummies
• Learning YANG

Examples

• OSM IM

Tooling

Custom toolchain called from Makefile.

The toolchain automatically generates different model documentations in doc/ (txt tree, html tree, uml). It also generates the Python model (ietf_ped_model.py) and finally it checks the example PEDs (*.yaml) against this model by loading them into the model.

Requirements:

• pip install pyang pyangbind
• pyang also needs to be install system wide to have correct paths to schema artefacts in system dirs

Call:

# validate model, build model, and test examples
make

# single targets
make validate # validate the model against ietf rules
make build # generate the python code model
make test # test the example PED files against model

TODOs Toolchain

• setup tooling (editor, pyang generation, documentation in README)
• create models folder in repo
• initial model to play with https://github.com/mpeuster/tng-sdk-benchmark/blob/feature-73/models/ped.yang
• tool to validate PED file (*.yml) against YANG model: Custom build
• Jenkins integration (can we also trigger tests etc. with pytest? tox?)
• Problem: mandatory fields are not mandatory in validation (ignore this for now)
• ...

TODOs Model

• complete model
• be more specific with units like CIDRs for addresses
• be more specific in many of the string types. See pattern keyword.

TODO Implementation

• make should place generated model to the right place in the source tree
• update implementation to support new model

Goal

Replace all legacy interactions with the PED model inside tng-sdk-bench with a pyang/pybind based solution using generated Python code.

[mpeuster]

Status: Model is finished so far (at least we should be able to express everything we expressed before).

Next step: Implementation in code!